This document proposes a method for preventing cheating of messages based on block cipher using a digital envelope. It begins with an introduction to the need for data security during storage and transmission. It then discusses the AES encryption algorithm and related work involving encryption for wireless devices. The proposed method uses AES key expansion techniques to generate multiple keys for encryption and decryption of messages using a digital envelope, packing the encrypted message and key into a single packet. It claims this prevents attackers from accessing sensitive data. Future work could expand this to image encryption and decryption applications.